<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    html, body {
      margin: 0;
      padding: 0;
    }
    .container {
      position: relative;
      height: 100vh;
    }
    .left {
      width: 100px;
      position: absolute;
      left: 0;
      background-color: darkgreen;
    }
    .right {
      width: 200px;
      position: absolute;
      right: 0;
      background-color: darkmagenta;
    }
    .middle {
      background-color: darksalmon;
      position: absolute;
      left: 100px;
      right: 200px;
    }
  </style>
</head>
<body>
  <div class="container">
    <div class="left">右边</div>
    <div class="middle">中间</div>
    <div class="right">左边</div>
  </div>
</body>
</html>